Non-insulin dependent diabetes mellitus (NIDDM) is an important chronic disease common in Hispanic adults. While data are limited, this condition has been thought to occur only rarely in Hispanic children. The recent observation of a number adolescent non-insulin dependent diabetic hispanics in Ventura County, California, suggests that NIDDM may be much more common in Hispanic youth than previously appreciated. The goals of the proposed research are to document that prevalence of this early onset form of NIDDM in Ventura County; to determine whether undiagnosed cases exit; to explore inheritance patterns in families with young onset NIDDM patients; and to explore the relationship of environmentally controllable risk factors such as obesity to early onset NIDDM. The proposed study will both allow us to evaluate the potential for further investigations, as well as provide preliminary data to support a future R01 submission.